Super Stain Treat?® for those stubborn Stains-  2.5 lbs granular- Treats to 20,000 gallons. Product Number: SST-C12 The hottest product for eliminating all kinds of metallic stains Super Stain Treat® replaces draining and acid washing. It is effective across the whole pH range. Super Stain Treat® is compatible with all surfaces including, marcite, fiberglass, gunite, vinyl and exposed aggregate. It is the first step in a two-step program for removing and prevention. Effectively removes stains from fiberglass. Granular concentrate is more powerful & concentrated than typical liquid stain removers. Delivers enhanced performance when it's needed most - unlike most liquid treatments (which break down when pH drops). Dollar for dollar, the most powerful stain remover ever made.